Rationally designed/constructed MnOx/WO3 anode for photoelectrochemical water oxidation

Abstract

Photoelectrocatalytic water splitting is an effective way to utilize the solar energy to solve the energy shortage. The valence band edge of WO3 located at ∼3V vs. normal hydrogen electrode (NHE), which can offer enough potential to kinetically oxidize water for oxygen evolution reaction. However, water oxidation reaction kinetics is sluggish when only WO3 is used as the photoanode. It is highly desirable to use cocatalyst to promote the kinetics. MnOx loaded on the WO3 photoanode through photodeposition methods improves the photoelectrochemical water oxidation performance. A maximum photocurrent density of composite photoanode is achieved with a deposition time of 3min, which is higher than that of pristine WO3 photoanode around 40%. MnO2 is not only a cocatalyst for water splitting but also for improving oxidation selectivity. We tried to use two means to load MnOx on WO3 photoanode material. It is observed that loading a moderate amount of MnOx on the WO3 by photodeposition can promote the performance of the WO3 photoanode.